This invention relates generally to vehicle warning systems, and particularly relates to short range transmissions by emergency and school bus vehicles on receivable on all 40 channels of citizen band radios, generally found turned on in semi-trucks.
In rural areas having small populations and hilly regions, winding narrow roads are the norm. They have speed limits of 55 mph and higher, and people tend to drive fast on these roads because they need to go long distances between towns. Due to the heavy weights of the trailers being towed, and the extra long braking distances required, semi-truck drivers and delivery truck drivers have difficulty stopping on a dime in the event of an emergency, or when a school bus in dropping off children, and all traffic must come to a stop. When a truck driver is climbing a hill, it would be difficult for him to bring his vehicle to a dead stop in the event of an emergency just over the hill. These occasions arise when emergency vehicles are parked and tending to cars along the side of the road or ambulances helping victims of traffic accidents. Furthermore, of special concern and interest to the present inventor, is the occurrence of school buses which have stopped to pick up or drop off children. When the children cross the road to go home, it is especially dangerous, because any semi-truck that must swerve to avoid a school bus stopped in the middle of the road would most certainly be in extreme risk of striking a child walking across the very pavement that the truck would have to go into in order to avoid the bus.
That is the most prevalent problem noticed by the present inventor. He finds especially when a school bus drops off a child, and that child has to cross the road, it is extremely dangerous if the drop off point is over a hill which carries truck traffic. Truck drivers find their biggest problem arises when they are traveling quickly down a road, coming over a hill, only to find that they have to slam on their brakes to avoid hitting a stopped school bus dropping off children. It is unpredictable where the school bus is stopped, as there are no road signs, nor are there any apparent stop signs to warn truck drivers about the impending danger.
Previously, there have been numerous attempts to produce a warning signal producing system for motor vehicle responsive to vehicle presence indicating radio wave signals emitted by another vehicle indicating its presence. However, the second vehicle, i.e. the one that needs to be warned, must have some sort of radio receiver which must be in the xe2x80x9cOnxe2x80x9d position at all times in order to receive such a signal. Needless to say, there are many vehicles which have no radio, non-operational radios, or incompatible radios. Therefore, the problem of having all vehicles with perfectly compatible radio receivers is difficult to overcome.
In the closest known prior art attempt to solve this problem, a citizens band radio and/or receiver was utilized. Such an attempt was made in U.S. Pat. No. 4,013,994 issued to Ragano on Mar. 22, 1977, which discusses such a vehicular warning system, including the use of decoders and selectively filtered pre-selected signals. However, in direct contradistinction to the present invention, a single pre-selected signal is taught in the ""994 patent. More recently, U.S. Pat. No. 4,403,208 issued to Hodgson, et al, on Sep. 6, 1983, relates to a warning signal producing apparatus for use in motor vehicles, also suffering from the same malady that a radio must be tuned and working for the signal to be received and coupled to a pre-existing audio stage piece of equipment.
Even more recently, U.S. Pat. No. 5,594,432 issued to Oliva, et al., on Jan. 14, 1997, for a traffic information warning system, includes a first and second oscillator for a first and second carrier frequency being reflective of a traffic situation. The receiver includes a scanning circuitry, in the form of a microprocessor, for scanning across a predetermined frequency range to detect carrier signals separated by the predetermined frequency difference, in addition to a demodulator for retrieving first and second modulating signals. The ""432 receiver uses a microprocessor to compare the first and second modulating signals for identical status and then having an announcing device for announcing a message. This system is untenable in rural situations, and is not applicable to rural areas.
U.S. Pat. No. 4,238,778 issued to Ohsumi on Dec. 9, 1998, discloses a radio frequency radio signal which has an audible warning that increases as the distance between the emergency motor vehicle and the motor vehicle to be warned decreases. As the emergency motor vehicle approaches to within 100 meters of a vehicle equipped with the warning signal receiver of that patent, the warning signal is supposed to be detected by the receiver. However, this feature, again, would not work in a rural situation where more than 100 meters, i.e. just over 300 feet, would be needed. U.S. Pat. No. 4,887,086 issued to Unser, et al., on Dec. 12, 1989, discloses a combination citizen band scanner and radar detector, including a radio receiver for use in a vehicle which combines a radar receiver, a receiver for the citizen band and a scanning receiver for public service bands which are controlled by a microprocessor. The public service scanning receiver would cover a range of public service bands from 37 MHz to 470 MHz, while the receiver for the citizen band would cover frequencies from 26 MHz to 28 MHz. This does not cover all the stations on a CB radio. Therefore, it is of limited use.
Therefore, it is an object of the present invention to provide an inexpensive transmitter for use on school buses and emergency vehicles in rural applications which will be able to transmit a signal receivable on all 40 channels of a citizens band radio within a predetermined range, the range will depend on its use in the rural areas and very low population areas. It is widely accepted that truck drivers have their citizens band radio in the xe2x80x9cOnxe2x80x9d position at all times, such that it would be able to receive a signal over any of the 40 channels on their citizens band radio.
It is also an object of the present invention to provide a 12-volt warning system so that it could be wired into all On and Off switches for the emergency or school bus vehicles.
It is yet a further object of the present invention to provide a device which only produces a signal, which would be much smaller with a minimal antenna and with no microphone to transmit voices.
It is yet a last object of the present invention to provide such a signal generator such that when a school bus or the like switches on its red flashing lights, the signal generator would begin to produce the signal.
In accordance with the objects and advantages as stated hereinabove, the present invention provides an inexpensive remote 40-channel signal generator to be installed on school buses, emergency vehicles, or the like. The signal is preferably a two tone signal which will be transmitted over any of the forty (40) channels on a citizens band radio, commonly found turned on in semi-trucks. The signal will only generate over a pre-selected relatively short distance range of from about 100 feet to about 2500 feet, depending upon the application in rural areas, or in extremely low population areas, so that trucks driving into a zone within a pre-selected distance can use their CB radios as receivers to receive a warning signal. The disclosed inexpensive signal generator would only produce a signal, would be much smaller than a regular CB radio with a minimal antenna, and with no microphone to transmit a voice. The device would run on a 12-volt system so that it could be wired into all On and Off switches for the vehicles, such that the system would be turned on automatically along with the school bus, emergency vehicle, railroad crossing, and the like.
The signal generator is an all channel CB tone transmitter to transmit a distinct signal over all the forty channels receivable by a standard citizens band radio. The range of the transmitter will be relatively short and will depend upon its use, whether it is to be used in the city or to be used in a rural area. The transmitter device would be made by utilizing a transmitter for a signal on all forty channels, much like a regular CB radio, only with a difference that this unit would only produce a signal, so it could but much smaller with a minimal antennae and without a microphone to transmit voice or other data signals. Preferably, a phase locked loop (PLL) tuner may be used to transmit on all FCC approved channels sequentially and automatically within several seconds. The required N-code input to the phase locked loop tuner is provided by a binary counter. An alternating two (2) tone audio signal may be mixed into the transmission before broadcasting.